Depilatory agents have been used for many years to remove unwanted hair from skin on the human body. The most common depilatory agents are thioglycolates, in particular alkaline earth metal thioglycolates such as calcium thioglycolate. A slight excess of alkalinity is often included in the composition in order to provide a reservoir of alkalinity to help maintain the alkalinity of the composition at a desired pH value, generally in a pH range of at least 10, such as about 12 to about 12.5. The foregoing are disclosed in the U.S. Pat. No. 4,121,904 and in Cosmetics—Science and Technology (edited by Balsam et al), Volume 2, John Wiley & Sons, Inc., 1972, New York, page 39–72.
Such depilatories are most commonly marketed in the form of creams or pastes. Following application to the skin from about 5 to about 15 minutes, these agents effectively remove the unwanted hair, generally without irritation of the human skin. These agents are also readily wiped or washed off, along with the degraded unwanted hair, with water.
The present invention relates to a substantially dry composition or article containing at least one oxidizing agent and at least one reducing agent and the uses thereof to remove hair from the skin. The following is a summary of various U.S. patents that disclose the use of oxidizing and reducing agents.
U.S. Pat. No. 3,341,418 describes a two-part aqueous composition in which the parts are mixed immediately before or during use with simultaneous evolution of heat. One part contains a reducing agent (e.g., thiourea) and the second part contains an oxidizing agent (e.g., hydrogen peroxide). These compositions are used for cosmetic applications such as skin and hair care, and in particular for shaving preparations.
U.S. Pat. No. 4,011,878 describes a process for permanently waving hair using a self-heating composition containing two aqueous components: one component containing a water-soluble sulfite, metabisulfite or bisulfite and thiourea, and a second component containing hydrogen peroxide. The two components are mixed prior to use, resulting in an exothermic reaction.
U.S. Pat. No. 4,206,068 discloses cleaning compositions for drains using oxidizing and reducing agents and an alkali metal hydroxide. To prevent a premature reaction of the oxidizing and reducing agents, the ingredients are kept separate until actual utilization for drain cleaning purposes.
U.S. Pat. No. 6,287,580 describes a self-heating cosmetic composition that includes a skin conditioning agent and a redox system based on iron powder (e.g., elemental iron, iron oxides and ferrous salts) and a high surface area catalyst (e.g., charcoal, alumina, clays, silica). The compositions are taught in different forms such as lotions, creams, emulsions, ointments, and pad applied formulations. The system is activated with moisture and air.